Printed on 2/13/2026
For informational purposes only. This is not medical advice.
The Acute Physiology and Chronic Health Evaluation II (APACHE II) is the most widely used ICU severity scoring system. It uses 12 acute physiological variables (worst values in first 24 hours of ICU admission), age points, and chronic health points to generate a score from 0 to 71. Higher scores correlate with higher predicted mortality and help guide clinical decision-making, resource allocation, and benchmarking.
Formula: APACHE II = Acute Physiology Score + Age Points + Chronic Health Points (0–71)
Disclaimer: This tool is for educational and informational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider with questions about your health.
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APACHE II is a severity-of-disease classification system applied within 24 hours of ICU admission. It uses 12 physiological measurements, age, and chronic health status to predict hospital mortality. Scores range from 0 to 71, with higher scores indicating greater severity.
It is primarily used for: ICU benchmarking and quality assessment, stratifying patients in clinical trials, guiding goals-of-care discussions, and comparing case-mix severity across ICUs. It is not intended as the sole determinant of treatment decisions for individual patients.
Use the worst (most abnormal) values during the first 24 hours of ICU admission. If a lab test was not performed, use normal values. The GCS should be assessed before sedation when possible.
Chronic health points (2 or 5) are given for severe organ insufficiency or immunocompromised state documented prior to admission: liver (cirrhosis, portal HTN), cardiovascular (NYHA IV), respiratory (chronic restrictive/obstructive/vascular disease), renal (chronic dialysis), or immunocompromised.
Use worst values from the first 24 hours of ICU admission.